The episode begins at the Wattersons'house. Richard is seen looking at a book, and looking in the fridge at the same time, while looking confused. Darwin points out to Gumball that he never sees Richard look confused at the fridge, with Gumball agreeing. Richard asks them where the salad is, with Richard mispronouncing the word "salad." Gumball corrects him, and says it's in the bottom of the fridge. Richard places a piece of lettuce on a plate in the kitchen, with Gumball being impressed about him taking it seriously. However, in the dining room, Gumball points out several other plates Richard has, with Richard giving somewhat true reasons how they help with his diet.
The next morning, Gumball and Darwin are eating their cereal. Richard goes into the kitchen, appearing more fat than he was last night. Darwin sees this as a roll neck sweater, but Richard says he's not wearing a roll neck sweater. Gumball takes notice and sees that it's Richard's actual neck. Gumball begins to doubt that Richard's diet is helping, though Richard denies it. Gumball also points out that the fridge has been consistently empty, prompting Richard to deflect their accusations by ordering groceries online. However, he becomes impatient waiting for them to arrive and decides to go with Gumball and Darwin to the grocery store instead. Unfortunately, Richard is too obese to properly get in his car, and attempts to fasten his seatbelt prompt the car to fall over on its side.
After that, Gumball and Darwin help Richard by dieting the right way. They begin by telling Richard to be open and honest and tells Richard if he has any hidden food. After Richard tries to throw them off, Gumball and Darwin just look in various places all over the house for hidden food. Eventually, they decide that they have seen enough and put him on "lock-down" in the shed.
Darwin stands guard near the shed while Gumball watches a surveillance feed to make sure Richard stays put. Gumball reports that he notices something, and upon further inspection, Darwin sees Richard eating a 'burger'. Darwin goes in the shed to confront Richard but notices that he is gone and that the 'burger' was a decoy. Darwin then looks up at the ceiling to find Richard drooling on him, causing Darwin to freak out. As he vigorously tries to wipe the saliva off, Richard escapes and gorges himself by the fridge.
The kids instead try to get Richard to work out through the use of food as a motivator and, after a synth-rock crossfade montage in which Richard gets more and more buff, the two call it a day. However, Richard continues to work out without them, and the next morning, the kids find him, grotesquely buff, having a fight with Mr. Robinson for being in the way of his car, waking the two up. Gumball and Darwin surmise that they created a monster before Mr. Robinson drives off with Richard on the car's hood, bound for the Elmore Mall.
The two set out to try to stop Richard, fearing embarassment, and track him through his aggressive selfie habits. Meanwhile, Richard makes Hexagon Lady uncomfortable, dives into a fountain to save a coin Alan threw in (and thus ruining his wish for world peace), and steals the tires off an ambulance to use as weights before being chased off. When Gumball and Darwin arrive at the scene, they overhear of a fire on West Elmore Boulevard, noticing that Richard is there posing with a hose.
At the scene of the fire, Richard continues to pose before a shocked crowd, preventing the fire department from being able to put the fire out. Doughnut Sheriff shows up and tries to tase Richard, but in the process, he only makes Richard's abs more defined. Gumball and Darwin finally show up and remind Richard of how much he misses food. Suddenly, Richard sees all of the food that the spectators are eating, causing him to take a step back and fall over. While doing so, he causes the hose to disconnect from a nearby fire hydrant, proceeding to spurt water upon the fire, putting it out.
Richard realizes that he went too far and decides to make it up to Gumball and Darwin by taking them out for pizza, ending the episode.
When Richard asked where the salad was, he said sa-lard. Lard is pure fat.
This is the second time Richard is seen buff. The first instance was seen in "The Car."
The face mask cream from "The Kids" reappears in Richard's mirror cabinet.
The nursery where the kids dropped off Nicole and Richard in "The Rerun" reappears in one of Richard's selfies.
The orchestral piece that plays after Richard comes out from diving into the water fountain to retrieve Alan's coin is Léo Delibes' Flower Duet from the opera Lakmé.
The record labeled "Rage Against the Humans" that Richard hid pizza in is a reference to the rock band Rage Against the Machine.
The scene where Gumball and Darwin are using food to get Richard to excercise could be a reference to the film Kung Fu Panda.
This episode is somewhat similar to the Family Guy episode called He's Too Sexy for His Fat, in which Peter becomes muscular and attractive but also becomes obnoxious and narcissistic because of his new look.